Natural history of multicystic kidney conservatively managed: a prospective study

Clinical Characteristics and Outcomes of Children with Unilateral Multicystic Dysplastic Kidney: A Cohort Study

OBJECTIVES

To study the clinical profile and outcomes of children with unilateral multicystic dysplastic kidney (MCDK).

METHODS

We assessed the clinical features and extrarenal manifestations in children with unilateral MCDK. These children were followed up to ascertain involution, compensatory hypertrophy and progression of chronic kidney disease (CKD) stage.

RESULTS

We enrolled 106 children with unilateral MCDK which was detected antenatally in 98 (92.4%), while evaluating for urinary tract infection in three (2.8%), and incidentally in five (4.7%) children. Abnormalities in the contralateral kidney and extrarenal manifestations at initial presentation were detected in 30 (28.3%) and 15 (14.2%), respectively. At a median (IQR) follow-up of 60 (32, 87) months, 34 (32.1%) children demonstrated complete involution of the MCDK, while 72 (67.9%) showed compensatory hypertrophy in the contralateral kidney. The median age at involution of MCDK was 48.5 (33, 86.5) months. Twenty-two (20.7%) children had non-regression of MCDK, and two (1.9%) underwent nephrectomy. Eight (7.5%) children developed hypertension and two children were detected to have proteinuria. One child, each, progressed to CKD stage 2 and stage 3a; and another child (0.9%) progressed to end stage kidney disease. None of the patients developed malignant transformation.

CONCLUSIONS

Majority of cases (92.4%) of MCDK had been detected antenatally. The rate of involution was 32.1% at a median follow-up of 60 months. Although, 28.3% of cases of MCDK had abnormalities in the contralateral kidney, progression of CKD to a higher stage occurred only in three (2.8%) cases.

The Outcome of Multicystic Dysplastic Kidney Disease Patients at King Abdulaziz Medical City in Riyadh

Background Multicystic dysplastic kidney (MCDK) is a type of kidney dysplasia consisting of many irregular, various-sized cysts divided by dysplastic renal tissue, which negatively impacts kidney function. MCDK is one of the most common renal congenital disorders seen in antenatal ultrasounds. The typical prognosis of MCDK is complete or partial involution that starts antenatally and continues postnatally. The aim of the study was to shed light on the overall outcome of patients with MCDK. Methods We retrospectively collected data on MCDK patients from 2016 until 2022 at King Abdulaziz Medical City, Ministry of National Guard Health Affairs in Saudi Arabia, Riyadh. The data included the recording of epidemiological data, radiological and laboratory reports, and the presence of urological or non-urologically associated anomalies. Results A total of 57 patients with MCDK were reviewed. Seven of them were excluded due to the diagnosis of bilateral MCDK, which was incompatible with life. Of the remaining 50 patients, the right kidney was affected in 52% of them. Most patients were diagnosed antenatally (98%). The mean duration of follow-up for the study was 48 months. Vesicoureteral reflux (VUR) was detected in 22% of the total sample. Overall, 90% of the patients underwent kidney involution. A small percentage had genitourinary anomalies (20%), while a larger percentage (48%) had extrarenal abnormalities. Conclusion Multicystic dysplastic kidney disease is relatively common in children. The prognosis is affected by the presence of genitourinary and non-genitourinary anomalies. Patients have an overall good prognosis with conservative management. Antenatal screening, diagnosis, and long-term nephrological follow-up are essential for the optimal management of patients.

Renal function in children with a congenital solitary functioning kidney: A systematic review

INTRODUCTION

Abnormal renal development that results in lack of function or development of one of two kidneys is known as congenital solitary functioning kidney (CSFK). Two well characterized sub-categories of CFSK are unilateral renal agenesis (URA) and multicystic dysplastic kidney (MCDK). This systematic review sought to evaluate the change in renal function in children ≤18 years old with a CSFK as a result of URA or MCDK.

METHODS

A literature search in MEDLINE and Embase was conducted (1946 to July 13, 2020). All relevant articles were retrieved and evaluated based on pre-selected criteria by two independent researchers. Data was then extracted from variables of interest and conflicts were resolved by a third researcher. The primary outcome was renal function, and the secondary outcomes were proteinuria and hypertension.

RESULTS

Forty-five studies were included, of which 49% (n = 22) were retrospective and/or 58% (n = 26) were cohort studies. A combined total of 2148 and 885 patients were diagnosed with MCDK or URA, respectively. The proportion of children with worsened renal function at follow-up was found to be 8.4% (95% CI: 5.2%-13.4%). Among the studies reporting renal function as a group mean or median at follow-up, 84% (21/25) had a GFR/CrCl above 90 (mL/min/1.73  m²/ml/min). In terms of secondary outcomes, the proportion of children with proteinuria and hypertension was found to be 10.1% (95% CI: 6.9%-14.6%) and 7.4% (95% CI: 5.0%-10.9%), respectively.

CONCLUSION

The risk of developing proteinuria (10.1%), hypertension (7.4%), and/or worsened renal function (8.4%) for children with CFSK as a result of MCDK or URA is low. However, the level of evidence in the literature is weak. Further research is needed to identify the predisposing factors that may differentiate the small subset of children with CSFK at a higher risk of developing adverse renal outcomes.

Approach to the postnatal sonographic evaluation of prenatally detected abdominopelvic cysts

Prenatally detected abdominal and pelvic masses are commonly cystic in morphology and usually seen on mid-trimester sonography. Sonography is the favored imaging modality for the postnatal evaluation of these lesions in newborns, given its availability, low cost, lack of ionizing radiation, lack of sedation, and high spatial resolution in small patients. The differential diagnosis of abdominopelvic cystic masses in newborns is broad given that they can arise from many organs and may have overlapping features on imaging. This article illustrates an approach to the postnatal sonographic evaluation of prenatally detected cystic abdominal and pelvic masses based on their anatomic location and distinctive sonographic characteristics, which can aid in an accurate diagnosis and guide appropriate management.

Renal growth slope in children with congenital and acquired solitary functioning kidneys

Purpose

This study aimed to analyze the renal growth slope in children with congenital and acquired solitary functioning kidneys.

Methods

This retrospective study included all renal ultrasonography examinations performed in children in the agenesis, multicystic dysplastic kidney (MCDK), or nephrectomy group between September 2002 and February 2019. We reviewed the images and recorded the contralateral kidney size only when there was no focal lesion. Linear mixed model or piecewise linear mixed model analyses with a time point of 24 months of age were performed.

Results

There were 132 patients, including 26 patients in the agenesis group, 35 in the MCDK group, and 71 in the nephrectomy group. The nephrectomy group showed the largest baseline kidney size (7.4 cm vs. 5.3 cm in the agenesis group [P<0.001] and 5.2 cm in the MCDK group [P<0.001]) and the smallest overall growth slope (0.04 cm/mo vs. 0.06 cm/mo in the agenesis group [P=0.004] and 0.07 cm/mo in the MCDK group [P<0.001]). However, considering the time point of 24 months for reaching adult renal function, there were significant changes in slope, from 0.1 cm/mo before 24 months of age to 0.03 cm/mo after 24 months of age in all three groups (P<0.001), without a significant difference among the groups.

Conclusion

Significant changes were found in the renal growth slope before and after 24 months of age, with no significant difference between congenital and acquired solitary functioning kidneys.

"Watch and Wait" Strategy for Multicystic Dysplastic Kidney (MCDK): Status Survey of Perceptions, Attitudes, and Treatment Selection in Chinese Pediatric Urologists and Pediatric Surgeons

To investigate the perceptions, attitudes, and treatment selection of Chinese pediatric urologists and pediatric surgeons regarding a "watch and wait" strategy for multicystic dysplastic kidney (MCDK). We used a cross-sectional survey in this study. We sent the questionnaire to pediatric urologists and pediatric surgeons to capture their views via the "Questionnaire Star" online survey platform between November and December 2019. The questionnaire contained the basic information and surgical experiences of the respondent, respondents' awareness regarding the counseling of prenatally-diagnosed MCDK and the treatment of MCDK, and respondents' knowledge regarding the imaging modalities, frequency, and duration of follow-up. Of the 200 questionnaires we sent, we received 151 responses. Of those 151 complete responses, most respondents were women (n = 104, 68.9%), pediatric urologists (n = 78, 51.6%), and practicing with at least 5 years of surgical experience (n = 112, 74.2%); 11.9% reported >20 years' experience. Eighty-two surgeons (54.3%) provided positive counseling for prenatally-diagnosed MCDK. Ninety-nine surgeons (65.6%) advocated conservative management for MCDK, and only 14.8% of respondents suggested limiting the use of radiographic evaluation for MCDK. Surgeons working in academic teaching facilities and those from East China were more likely to select a "watch and wait" strategy. Chinese pediatric urologists and pediatric surgeons have inadequate knowledge of the "watch and wait" strategy for MCDK. An expert consensus on the strategy of "watch and wait" for MCDK in China is urgently needed to promote the application of this non-surgical treatment mode in clinical practice. A larger sample size is required to fully identify the current opinion of Chinese pediatric urologists and pediatric surgeons regarding the management of MCDK.

Trends in surgical management of multicystic dysplastic kidney at USA children's hospitals

INTRODUCTION AND OBJECTIVE

Multicystic dysplastic kidney (MCDK) is a congenital renal cystic disease often incidentally diagnosed in children. Historically, children with MCDK underwent early nephrectomy because of concerns for the development of hypertension or malignancy. Over the last decade, management recommendations have not supported routine early surgical removal of MCDK. The study authors sought to determine the current trends in the use of nephrectomy for MCDK in US children's hospitals because national practice patterns have not been investigated.

METHODS

A population-based retrospective cohort study using the Pediatric Health Information System (PHIS) was conducted. The study population was comprised of patients aged 0-18 years with a diagnosis of MCDK (International Classification of Diseases-9th revision, code 753.19) admitted to the inpatient department of the study hospital between January 2006 and September 2015. Patients with additional renal anomalies including polycystic kidney, medullary cystic kidney, and medullary sponge kidney were excluded, as were patients treated in a hospital that did not contribute data to the PHIS continuously throughout the study period. Trends in the annual proportion of nephrectomies performed were analyzed among admissions in the study population, along with patient clinical and demographic information.

RESULTS

A total of 3792 MCDK admissions, in 34 hospitals, were included in the study. Overall, 569 nephrectomies were performed during the study period. The proportion of nephrectomy decreased annually by 9.2% on average, from 22.1% in 2006 to 7.3% in the first 3 quarters of 2015. No significant trends were observed in the annual number of overall MCDK admissions or patient age at procedure among patients who had a nephrectomy. Among nephrectomies, 84.2% were open and 15.8% were minimally invasive procedures (laparoscopic non-robotic, 10% and robotic, 5.8%). The proportion of minimally invasive nephrectomies increased annually by 13.7%, from 8% in 2006 to 29% in 2015.

DISCUSSION

Trends in the use of nephrectomy for MCDK at a national level have not been previously reported. This study is limited by the use of inpatient discharge data, which did not allow estimating the true rate of nephrectomy in patients born with MCDK.

CONCLUSIONS

During the study period, there has been a decrease in the use of nephrectomy for MCDK in pediatric hospitals, along with a concurrent increase in utilization of minimally invasive techniques to perform nephrectomies. These results suggest that in general, urologists at freestanding children's hospitals are heeding recommendations for observation and against routine early surgical removal of these kidneys; although trends in the use of nephrectomy varied between hospitals, there is room for continued improvement in following these recommendations.

A clinical predictive model of renal injury in children with congenital solitary functioning kidney

BACKGROUND

Solitary functioning kidney (SFK) is an important condition in the spectrum of congenital anomalies of the kidney and urinary tract. The aim of this study was to describe the risk factors for renal injury in a cohort of patients with congenital SFK.

METHODS

In this retrospective cohort study, 162 patients with SFK were systematically followed up (median, 8.5 years). The primary endpoint was time until the occurrence of a composite event of renal injury, which includes proteinuria, hypertension, and chronic kidney disease (CKD). A predictive model was developed using Cox proportional hazards model and evaluated by c statistics.

RESULTS

Among 162 children with SFK included in the analysis, 132 (81.5%) presented multicystic dysplastic kidney, 20 (12.3%) renal hypodysplasia, and 10 (6.2%) unilateral renal agenesis. Of 162 patients included in the analysis, 10 (6.2%) presented persistent proteinuria, 11 (6.8%) had hypertension, 9 (5.6%) developed CKD stage ≥ 3, and 18 (11%) developed the composite outcome. After adjustment by the Cox model, three variables remained as independent predictors of the composite event: creatinine (HR, 3.93; P < 0.001), recurrent urinary tract infection (UTI) (HR, 5.05; P = 0.002), and contralateral renal length at admission (HR, 0.974; P = 0.002). The probability of the composite event at 10 years of age was estimated as 3%, 11%, and 56% for patients assigned to the low-risk, medium-risk, and high-risk groups, respectively (P < 0.001).

CONCLUSION

Our findings have shown an overall low risk of renal injury for most of infants with congenital SFK. Nevertheless, our prediction model enabled the identification of a subgroup of patients with an increased risk of renal injury over time.

Evidence-based treatment of multicystic dysplastic kidney: a systematic review

OBJECTIVES

There is a lack of a standardised protocol for the investigation and non-operative management of paediatric multicystic dysplastic kidney (MCDK). Institutional protocols for non-operative management remain essentially ad hoc. The primary outcome of this systematic review is to establish the incidence of hypertension associated with an MCDK. The secondary outcome is to determine the malignancy risk associated with an MCDK. The tertiary outcome is to assess the rate of MCDK involution. Subsequent to these, an evidence-based algorithm for follow-up is described.

METHODOLOGY

A systematic review of all relevant studies published between 1968 and April 2017 was performed using the Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines. Studies were identified by specific inclusion and exclusion criteria, all of which included data relevant to the primary, secondary and tertiary outcomes. Hypertension was defined as systolic blood pressure greater than the 95th centile for gender, age and height centile. Subset analysis was performed for hypertension associated with an MCDK.

RESULTS

The primary outcome measure revealed a 3.2% (27/838) risk of developing hypertension associated with an MCDK. The secondary outcome measure noted a 0.07% malignancy risk (2/2820). The tertiary outcome measure established that 53.3% (1502/2820) had evidence of involution of the dysplastic kidney. A total of 44 cohort studies (2820 patients) were analysed.

CONCLUSION

Given the low risk of hypertension and malignancy, which is similar to the general population, the current conservative non-operative pathway is an appropriate management strategy. An algorithm to help support clinicians with ongoing management is proposed.

Multicystic dysplastic kidney: Assessment of the need for renal scintigraphy and the safety of conservative treatment

OBJECTIVES

To assess the need for implementing renal scintigraphy in the diagnosis of the multicystic dysplastic kidney (MCDK) and the safety of its conservative treatment.

MATERIAL AND METHODS

A retrospective study of patients with unilateral MCDK was conducted at our centre from January 2005 to August 2015. We calculated the positive predictive value (PPV) of ultrasonography, taking renal scintigraphy and pathology as the gold standard. We calculated a survival curve according to the Kaplan-Meier method to assess the annual probability of spontaneous resolution of the multicystic kidney.

RESULTS

Fifty-six patients were identified, 48 (85.7%) of whom had a prenatal diagnosis. Thirty eight (67.9%) of the patients were males, and the left side was affected in 33 (58.9%) of the patients. We observed associated urological abnormalities in 22 (39.29%) patients, with vesicoureteral reflux the most common (8, 14.29%). Seven patients (12.5%) developed renal failure. Forty-nine (87.5%) patients developed compensatory contralateral renal hypertrophy. Of the 33 patients who underwent surgery, the pathology results confirmed the MCDK diagnosis in 32. Compared with scintigraphy and pathology, the PPV of ultrasonography was 100% and 97%, respectively. The rate of spontaneous involution was 5.4% at 3 months of life, 11.3% at 2 years and 38.4% at 5 years.

CONCLUSIONS

In our experience, the conservative treatment of MCDK, until at least 5 years of age, is safe. Our data suggest that performing scintigraphy is not required for these patients, which means lower radiation exposure, as well as financial savings.

Update on Multicystic Dysplastic Kidney

Multicystic dysplastic kidney (MCDK) is the most common cause of cystic disease in children. It is characterized by multiple non-communicating cysts of varying sizes with no identifiable normal renal parenchyma. The incidence ranges from 1 in 1000 to 4300 live births, and it is one of the most commonly detected anomalies on prenatal ultrasound. MCDK has been shown to follow a benign course with relatively few sequelae and therefore should be managed conservatively. Currently, the key clinical questions revolve around the detection of anomalies in the contralateral kidney and follow-up imaging. The recent literature suggests that very limited radiographic evaluation of the MCDK is needed. The use of voiding cystourethrogram or nuclear medicine renal scans should be directed by any abnormalities on renal ultrasound or the development of urinary tract infections.

Neonatal polycystic kidney disease

This article provides an up-to-date comprehensive review and summary on neonatal polycystic kidney disease (PKD) with emphasis on the differential diagnosis, clinical manifestations, diagnostic techniques, and potential therapeutic approaches for the major causes of neonatal PKD, namely hereditary disease, including autosomal recessive and autosomal dominant PKD and nonhereditary PKD, with particular emphasis on multicystic dysplastic kidney. A brief overview of obstructive cystic dysplasia and simple and complex cysts is also included.

Multicystic dysplastic kidney: Impact of imaging modality selection on the initial management and prognosis

OBJECTIVE

To evaluate the impact of imaging modalities on the evaluation and prognosis of children with multicystic dysplastic kidney (MCDK) disease.

PATIENTS AND METHODS

A retrospective analysis of all children with MCDK diagnosed from 2004 until 2012 was performed. The study included 63 patients for whom all postnatal imaging modalities were available: renal bladder ultrasound (RBUS), dimercaptosuccinic acid scan (DMSA) and voiding cystourethrogram (VCUG). Cases with major congenital abnormalities or incomplete data were excluded. Abnormalities in the contralateral kidney and the fate of MCDK were also addressed.

RESULTS

At diagnosis, the average age was four-and-a-half months. The majority of cases were detected antenatally (87%). Postnatal RBUS and DMSA scans established the diagnosis of MCDK in 92% and 98% of patients, respectively. DMSA showed photopenic areas in the contralateral kidneys in 10% of patients; all of them had hydronephrosis and were confirmed to have vesicoureteral reflux (VUR). Contralateral VUR was detected in 16 patients; 63% of them had hydronephrosis. After a mean follow-up of three-and-a-half years, involution occurred in 62% of patients and the involution rate was inversely proportional to the initial size.

CONCLUSIONS

The classical appearance of MCDK on RBUS was sufficient to establish the diagnosis in most patients. DMSA scan was more accurate in confirming the diagnosis and evaluating the contralateral kidney. Selective screening for VUR in patients with contralateral hydronephrotic kidney should be considered.

The natural history of the multicystic dysplastic kidney--is limited follow-up warranted?

OBJECTIVE

Imaging of patients with multicystic dysplastic kidney (MCDK) has increased over the past three decades. This increased use of imaging has provided additional insights into the natural history of MCDK. The present study looked at this data for predictors of involution and associated anomalies.

METHODS AND MATERIALS

Institutional review board approval was obtained for this retrospective study. The University of Michigan Departments of Urology and Radiology records were searched to identify unilateral MCDK patients during 1980-2012. Available clinical, radiological and surgical records were reviewed, and pertinent data were recorded. The log-rank test and a Cox proportional regression analysis were performed to identify predictors of MCDK involution. Probability of involution over time was assessed using Kaplan-Meier methodology.

RESULTS

301 unilateral MCDKs were identified; 195 (64.8%) were detected antenatally. Of the MCDKs found, 136 (45.2%) were in girls; 160 (53.2%) were right-sided. Mean size at baseline was 5.0 ± 0.2 cm (Mean ± SE). Associated abnormalities included: contralateral ureteropelvic junction obstruction (n = 10; 3.3%); contralateral ureterovesical junction obstruction/primary megaureter (n = 6; 2.0%); ipsilateral VUR (n = 21; 7.0%); contralateral VUR (n = 63; 20.1%); and renal fusion anomaly (n = 4; 1.3%). The cumulative probability of involution was: 9.8% at one year, 38.5% at five years, and 53.5% at ten years of age. Baseline MCDK size was the only significant predictor of involution at bivariate (p < 0.0001) and multivariate (p < 0.0001; HR 0.58 [95% CI: 0.49, 0.69]) analyses. No MCDK developed malignancy during the follow-up period.

CONCLUSION

As many MCDKs eventually involute and the risk of associated malignancy appears to be very low, there is no absolute indication for nephrectomy. Based on the data and other recent studies, it is believed that pediatric MCDK patients with no other urologic abnormalities can safely tolerate more limited urological and radiological follow-up.

Single center experience in patients with unilateral multicystic dysplastic kidney

OBJECTIVE

To determine the clinical features, long-term outcomes, and additional urological anomalies of patients treated for multicystic dysplastic kidney (MDK).

MATERIALS AND METHODS

Patients with MDK who were followed between January 2004 and October 2012 were reviewed retrospectively. Demographic, clinical, laboratory, and radiological data were evaluated.

RESULTS

A total of 68 patients with MDK were followed for a mean period of 46.8 ± 32.4 months. MDK was detected by antenatal ultrasound in 64 (94.1%) of the patients. Ten patients had (14.7%) additional urological anomalies in contralateral kidney. Vesicoureteral reflux was found in five patients (7.3%). Other urological anomalies were megaureter (two), cortical renal cyst (two), ureteropelvic junction obstruction (one), and renal ectopy (one). Urinary tract infection was detected in 14 (20.5%) patients. Four (5.9%) patients had hypertension. Compensatory hypertrophy was detected in 29 (42.6%) patients. Eight (11.8%) of these 29 patients had glomerular hyperfiltration and three (4.4%) of these eight patients also had proteinuria. Follow-up ultrasound revealed complete involution in 19 (35.8%) patients. Nephrectomy was performed in 15 (22.0%) patients. Indications of nephrectomy were, recurrent urinary infection (four), hypertension (three), ureterocele (two), renal calculi (one), flank pain (one), hematuria (one), persistent large cystic kidney (three), and atypical US findings (two).

CONCLUSION

In patients with MDK, depending on the clinical, laboratory, and radiological findings, appropriate timing of operation by multidisciplinary approach is important for early detection and treatment of any possible complications.

The relationships between renal compensatory hypertrophy etiologic factors and anthropometric development in the pediatric age group

OBJECTIVE

To evaluate the factors associated with compensatory hypertrophy in the functional kidneys of children.

METHODS

The medical files of patients with a solitary functional kidney were reviewed retrospectively. Data regarding anthropometric measurements, functional renal length, functional renal length of standard deviation score (SDS) of functional kidney at diagnosis, and end of follow-up were obtained. Patients were divided into 2 groups, those with a unilateral kidney function of <10% (hypoplasia, dysplasia, and atrophy, group 1) and those with a solitary kidney (agenesis, and multicystic dysplastic kidney, group 2).

RESULTS

A total of 126 patients (70 boys) were evaluated. Both the sizes of the functional kidney and functional kidney SDS values at diagnosis were greater in group 1 relative to group 2. At the end of the follow-up period, anthropometric values including functional kidney size were higher in group 2. Functional kidney size of 2 SDS above the normal was mostly predictive at age 17.5 months (odds ratio [OR] 5.06) and at a body height of 82 cm (OR 5.57).

CONCLUSION

The most determining factors for renal length SDS values were age and height. Solitary kidneys complete compensatory hypertrophy by 17.5 months of age, and after that their growth continues in parallel to normal growth.

Compensatory enlargement of a solitary functioning kidney during fetal development

OBJECTIVE

To determine the degree of compensatory enlargement, and its time of onset, of the solitary functioning kidney (SFK) in fetuses with unilateral renal agenesis (URA) or unilateral multicystic kidney dysplasia (MCKD).

METHODS

This was a retrospective study of fetuses with URA or MCKD diagnosed prenatally and confirmed postnatally in the period from January 1999 to May 2011. Fetuses with any other congenital anomalies were excluded. Measurements of kidney length were retrieved from our prenatal ultrasound database and a nomogram was established and compared with that for normal kidney length.

RESULTS

In total, 67 fetuses were identified, 60 with MCKD and seven with URA, for which we obtained 147 kidney length measurements from our database. Mean gestational age at time of measurement was 29.7 (range, 18.4-36.7) weeks. Compensatory enlargement, defined as renal length >95(th) percentile for gestational age, was demonstrated in 87% of the MCKD cases and 100% of the URA cases (88% of cases overall). We estimated the mean enlargement for an SFK (defined as difference from 50(th) percentile for normal renal length) at 36 weeks' gestation to be 23.1% (9.25 mm), with the mean value being 11.4% (5.04 mm) greater than the 95(th) percentile for a normal kidney at this gestational age. Compensatory enlargement of SFKs was evident from the 20(th) week of gestation onwards.

CONCLUSION

Compensatory enlargement of SFKs occurs in almost 90% of fetuses with MCKD or URA, and may be observed from the 20(th) week of gestation onwards.

Cowden disease and multicystic dysplastic kidney: increased risk of renal cancer?

Unilateral multicystic dysplastic kidney is one of the most frequently identified urinary tract abnormalities in children. Although it can be an isolated finding, it is often associated with other anomalies of the kidney and urinary tract. It has also been described in association with other multisystemic disorders of known genetic aetiologies. Cowden disease (CD) is a rare autosomal-dominant disorder with age-related penetrance characterized by benign and malignant hamartomatous lesions affecting derivatives of all three germ cell layers. Hamartomas can emerge in virtually every organ, but are mostly found in the skin and gastrointestinal tract. We report a 7-year-old patient presenting with unilateral multicystic dysplastic kidney and CD, a hitherto unknown association in paediatrics, which raises the question of an increased risk of renal cancer.

Unilateral multicystic dysplastic kidney: does initial size matter?

BACKGROUND

We report the long-term follow-up of children with antenatally detected unilateral multicystic dysplastic kidney (MCDK) who were followed between 1985 and 2009.

METHODS

Involution rates were documented over time based on the initial size of the MCDK, as documented on postnatal ultrasound (USS), as well as long-term complications and renal function.

RESULTS

In 323 patients (182 male), 10 % of MCDK had involuted, as evidenced on the first postnatal USS, with survival function analysis showing the probability of complete involution to be 35 % in 249 patients by 2 years of age, 47 % in 180 patients by 5 years of age and 62 % in 94 patients by 10 years of age. There was a significant difference in the involution rates of MCKD at the 10-year follow-up between MCDK with an initial size of >5 cm versus MCDK with an initial size of ≤5 cm (p < 0.0001). No patients in the whole cohort developed sustained hypertension or malignancy during a median follow-up of 10.1 years (range 0.3-15.4 years). Median estimated glomerular filtration rate (eGFR) in 76 patients (7 at 5 years, 69 at 10 years) was 93 ml/min/1.73 m(2) (range 46-175 ml/min/1.73 m(2)), with 40 (53%) having an eGFR of between 90 and 140 ml/min/1.73 m(2). Twenty-three (30 %) of the 76 patients at 10 years had normal eGFR (90-140 ml/min/1.73 m(2)) as well as complete involution of the MCDK, compensatory hypertrophy of the contralateral kidney, no proteinuria and no hypertension.

CONCLUSIONS

Larger MCDK at birth are less likely to involute during the first decade of life. However, conservative management remains justified due to the lack of complications. A minority of patients fulfil current criteria for discharge from specialty follow-up at 10 years.

Early risk factors for neonatal mortality in CAKUT: analysis of 524 affected newborns

BACKGROUND

Congenital abnormalities of the kidney and urinary tract (CAKUT) are significant causes of morbidity. The aim of the study was to determine predictive factors of mortality in newborns with CAKUT.

METHODS

All 29,653 consecutive newborns hospitalized in a tertiary neonatal unit between 1996 and 2006 were evaluated. The main outcome was neonatal mortality. The variables analyzed as risk factors were maternal age, first pregnancy, low birth weight (LBW), prematurity, oligohydramnios, and CAKUT associated with other malformations (Associated CAKUT).

RESULTS

CAKUT was detected in 524 newborns, with an overall prevalence of 17.7 per 1,000 live births. A total of 325 (62%) cases were classified as urinary tract dilatation, 79 (15.1%) as renal cystic disease, and 120 (22.9%) as other subgroups. In the urinary tract dilatation subgroup, independent risk factors for early mortality were Associated CAKUT [odds ratio (OR) 20.7], prematurity (OR 4.5) LBW (OR 3.8), oligohydramnios (OR 3.0), and renal involvement (OR 3.0). In the renal cystic disease subgroup, two variables remained associated with neonatal mortality: LBW (OR 12.3) and Associated CAKUT (OR 21.4).

CONCLUSION

The presence of extrarenal anomalies was a strong predictor of poor outcome in a larger series of infants with CAKUT.

Clinical course of 822 children with prenatally detected nephrouropathies

BACKGROUND AND OBJECTIVES

With the advent of fetal screening ultrasonography, the detection of congenital anomalies of the kidney and urinary tract (CAKUT) in utero has permitted early management of these conditions. This study aims to describe the clinical course of a large cohort of patients with prenatally detected nephrouropathies.

DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS

In this retrospective cohort study, 822 patients were prenatally diagnosed with CAKUT and systematically followed up at a tertiary Renal Unit for a median time of 43 months. Variables included in the analysis were sex, laterality, fetal ultrasonography (isolated versus associated hydronephrosis), and presence/absence of nephrouropathies. The events of interest were urinary tract infection, surgical interventions, hypertension, CKD, and death. Survival analyses were performed to evaluate time until occurrence of the events of interest.

RESULTS

Urinary tract infection occurred in 245 (29.8%) children, with higher risk in females (hazard ratio=1.30, 95% confidence interval=1.02-1.70, P=0.05); 22 patients (2.7%) had hypertension, and 49 (6%) patients developed CKD. The risk of CKD was greater in patients with associated hydronephrosis (hazard ratio=5.20, 95% confidence interval=2.90-9.30, P<0.001). Twelve patients (1.5%) died during follow-up. Death was significantly associated with being born during the first period of the study (hazard ratio=6.00, 95% confidence interval=1.60-22.50, P<0.001), associated hydronephrosis (hazard ratio=9.30, 95% confidence interval=2.90-29.30, P<0.001), and CKD (hazard ratio=170.00, 95% confidence interval=41.00-228.00, P<0.001).

CONCLUSIONS

In our series, the clinical course of prenatally detected CAKUT was heterogeneous, and those infants with associated hydronephrosis at baseline were identified as a high-risk subgroup.

Indications and relative renal function for paediatric nephrectomy over a 20-year period

BACKGROUND

The indications for partial or total nephrectomy for urological reasons are not clearly documented in the paediatric surgical literature and there are only a limited number of publications on this subject.

PURPOSE

In order to clarify the situation in our centre, we reviewed our own indications for nephrectomy over a 20-year period.

METHODS

Medical records of patients who underwent nephrectomy for urological and oncological causes between May 1990 and October 2010 at our centre were retrospectively reviewed. Indications for nephrectomy were noted. Renal function was noted for urological cases.

RESULTS

A total of 357 nephrectomies were undertaken; out of these, 241 cases were for urological causes and 116 for oncological reasons. The majority of total nephrectomies were performed for multicystic dysplastic kidneys, reflux nephropathy, pelvi-ureteric junction obstruction and dysplasia. Eighty-seven patients exhibited no function at the time of nephrectomy. Of the remainder, 17 had <5% function, 18 had 5-10% function, 5 had 10-15% function and 2 patients had 15-20% function.

CONCLUSIONS

This is the largest series of nephrectomies in the paediatric surgery literature to date. The majority of nephrectomies were undertaken for urological conditions with relative renal function of <10% and could not have been usefully preserved in situ. We suggest that kidneys with >10% function should not be routinely removed.

Urinary levels of TGF β-1 and of cytokines in patients with prenatally detected nephrouropathies

This study aimed to identify noninvasive biomarkers of clinically significant nephrouropathies in patients with antenatal renal and/or urinary tract alterations. Spot-urine levels of interleukin-6 (IL-6), transforming growth factor-β1 (TGF-β1) and tumor necrosis factor-α (TNF-α) were measured in 100 patients with antenatal detected nephrouropathies. Patients were divided in idiopathic hydronephrosis (n = 47), urinary tract malformations (n  = 35), and dysplastic kidneys (n = 18). Urinary concentrations of TGF-β1, IL-6, and TNF-α were compared between groups according to clinical and image findings. Receiver-operating characteristic (ROC) curves were analyzed for the overall diagnostic accuracy of TGF-β1, IL-6, and TNF-α levels in discriminating infants with nephrouropathies. No significant differences in urinary TGF- β1, IL-6, and TNF-α levels were found in the comparison between the groups. TGF-β1 levels tended to be higher in patients with renal hypodysplasia compared to idiopathic hydronephrosis (p = 0.07). Twenty-nine patients had reduced DMSA uptake. In these cases, absolute urinary concentration of TGF-β1 and levels standardized for creatinine were significantly higher than in patients with normal DMSA uptake, while IL6 and TNF-α did not differ between groups. Urinary cytokine measurements were not useful as a screening test for clinically significant nephrouropathies. Conversely, increased concentrations of TGF-β1 pointed out to renal damage as indicated by reduced DMSA uptake.

Long-term risk of chronic kidney disease in unilateral multicystic dysplastic kidney

The clinical spectrum of renal dysplasia includes the non-functioning multicystic dysplastic kidney (MCDK). We report our experience of the outcome of unilateral MCDK and its contralateral kidney in 101 children with the diagnosis of MCDK from 1985 to 2009. Data collected included urine protein/creatinine ratio, estimated GFR (eGFR), blood pressure, surgical intervention, renal length and abnormalities of the contralateral kidney, and the involution rate. There was a predominance of left-sided MCDK. Diagnosis was made prenatally in 86.7%. Contralateral abnormalities included vesicoureteral reflux (16.8%), UPJ obstruction (4.1%), and megaureter (2.4%). Complete involution of MCDK occurred within 5 years in 60%. Compensatory hypertrophy of the contralateral kidney to >97% occurred in 74.1%. Nephrectomy was performed in 19.8%. There was an increased risk of chronic kidney disease (CKD) stage ≥ 2, and hypertension in those with contralateral abnormalities (p<0.0001; p<0.001 respectively). In those without contralateral abnormalities, hyperfiltration with mean eGFR of 149 ± 13 ml/min/1.73 m(2) was seen in 32% and proteinuria in 9.8%. There was a significantly inverse relationship between proteinuria and eGFR (p<0.0001). In conclusion, children with contralateral abnormalities are at risk for developing decreased kidney function, whereas a substantial number of patients with no obvious contralateral abnormalities have markers of renal injury. Therefore, systematic follow-up of all patients is recommended.

Imaging chronic renal disease and renal transplant in children

At Great Ormond Street Hospital we have the highest number of paediatric renal transplant patients in Europe, taking cases from across the United Kingdom and abroad. Our caseload includes many children with rare complicating medical problems and chronic renal failure related morbidity. This review aims to provide an overview of our experience of imaging children with chronic renal failure and transplants.

Management and etiology of the unilateral multicystic dysplastic kidney: a review

In children, unilateral multicystic dysplastic kidney (MCDK) is one of the most frequently identified urinary tract abnormalities. A variety of proposed etiologies has been associated with the underlying pathogenesis of MCDK. These include genetic disturbances, teratogens, in utero infections, and urinary outflow tract obstruction. From 5-43% of the time, MCDK has associated genito-urinary anomalies, both structural and functional in nature. A review of the literature reveals that involution rates are reported to be 19-73%, compensatory hypertrophy of the contralateral kidney occurs from 24-81% of the time, and estimated glomerular filtration rates (GFRs) (by the Schwartz formula) range from 86-122 ml/min per 1.73 m(2) body surface area. Most authors suggest serial ultrasonography to monitor contralateral growth, routine blood pressure monitoring, and a serum creatinine monitoring algorithm. The risk of hypertension in those with MCDKs does not appear to be greater than that of the general population, and the rates of malignant transformation of MCDK are small, if at all increased, in comparison with those in the general population. If the patient develops a urinary tract infection or has abnormalities of the contralateral kidney, shown on ultrasound, a voiding cystourethrogram is recommended. Finally, the body of literature does not support the routine surgical removal of MCDKs.

Unilateral multicystic dysplastic kidney: single-center experience

Multicystic dysplastic kidney (MCDK) is one of the most common renal abnormalities in children. The aim of our study was to evaluate the clinical course and outcome of patients with MCDK. Ninety pediatric patients with unilateral MCDK followed by the Pediatric Nephrology Department of Bakirkoy Maternity and Children's Hospital between 1990 and 2007 were included in this retrospective study. The dimercaptosuccinic acid radionuclide scan revealed no function in MCDK in all of our patients. Voiding cystourethrogram was performed in all patients. Twenty patients (22.2%) had abnormalities in the contralateral kidney. Nephrectomy was performed in 41 patients (45.5%). Twelve patients had undergone routine nephrectomy before 1996. Since then, patients have been followed up conservatively, and nephrectomy has been performed only when indicated. Indication of nephrectomy was arterial hypertension in 16 patients (23.1%), recurrent urinary tract infection (UTI) in 11 (15.9%), and severe abdominal pain in two (2.8%). Hypertension was noted within the first year of life in all patients except two. MCDK completely involuted in 39.3% within 48 months. There was no malignant transformation, proteinuria, or renal failure. In conclusion, hypertension is often noticed in infants with MCDK. Uninephrectomy leads to normalization. However, prospective studies are needed to exclude a spontaneous improvement of hypertension.

[Multicystic kidney disease in a segment of horseshoe kidney: an uncommon combination of malformations]

Multicystic dysplasia is the most common type of renal cystic disease, and it is one of the most common causes of an abdominal mass in infants. The contralateral system is also frequently abnormal. The most commonly associated anomalies are contralateral ureteropelvic junction obstruction and contralateral vesicoureteral reflux. In a few cases, multicystic dysplasia involves a horseshoe kidney or one pole of a duplex kidney. We present a female patient diagnosed with this condition at 9 years old, when she was being studied due to recurrent abdominal pain. The renal function was normal.

[Multicystic dysplastic kidney disease: update and information for parents at the time of prenatal diagnosis]

Multicystic kidney disease (MCKD) is the most common form of Congenital Abnormality of Kidney and Urinary Tract (CAKUT). This anomaly of renal development is characterized by unilateral enlarged cystic formations and fibrous dysplastic parenchyma. The long-term prognosis is usually good; however because of reduced nephron mass, an early prevention of cardiovascular risk and nephrotoxicity is recommended. A lifelong follow-up of blood pressure, serum creatinine and microalbuminuria seems logical as well as in other patients with a single kidney. MCKD is usually diagnosed during pregnancy so that parents often question about long-term prognosis and follow-up. Therefore, we propose an information sheet for parents.

Non-surgical management of multicystic dysplastic kidney

OBJECTIVES

To better define the outcome and association of multicystic dysplastic kidney (MCDK) with hypertension, vesico-ureteric reflux (VUR), infection and cancer, as there is no consensus on the management of patients born with MCDK. The risk of cancer has dictated the surgical management of the disease in the past.

METHODS

The Medline database was searched for articles published between 1965 and 2006 and written in the English language, and containing the keywords 'multicystic dysplastic kidney'.

RESULTS

The inclusion criteria were met by 105 reports that were subsequently analysed. Of MCDK, 60% regress or involute within 3 years. About 25% of patients will have VUR into the contralateral kidney, of which 90% is grade <or=3. The risk of urinary tract infection appears to be associated with VUR or coexistent abnormalities rather than the MCDK. The risk of hypertension is no greater than that in the general population and nephrectomy is usually not curative. The overall risk of Wilms' tumour developing in a MCDK is <1 in 2000. All reported Wilms' tumours were identified before 4 years of age and 70% presented as a palpable mass.

CONCLUSIONS

Published reports support the non-surgical management of MCDK. Common practice has been to remove palpable or growing MCDKs, although these represent a very small fraction of MCDKs. In theory, ultrasonographic surveillance until 4 years old might allow the earlier detection of a Wilms' tumour, and decrease the intensity of chemotherapy and improve prognosis. Previous reports do not prove or disprove this concept, and the appropriate frequency of surveillance is not evident.

Simple multicystic dysplastic kidney disease: end points for subspecialty follow-up

Simple multicystic dysplastic kidney (MCDK) disease, defined as unilateral MCDK without other genitourinary tract involvement, portends an excellent prognosis. Nevertheless, its long-term management remains undefined. This study aims to provide subspecialty discharge recommendations for these patients. We identified eighty patients with simple MCDK disease by renal ultrasound between 1996 and 2006. Their charts were reviewed for growth of the contralateral kidney, involution of the MCDK, and incidence of complications, specifically hypertension, chronic renal insufficiency (CRI), urinary tract infection (UTI), and malignancy. Mean follow-up was 5 years. At approximately 1 year, 59% of unaffected kidneys were hypertrophied (>or=95th percentile for age/height) and 100% were >50th percentile. With continued follow-up, 80.3% of unaffected kidneys were hypertrophied. Likewise, at 1 year, 71.2% of MCDKs assessed were either involuting or had disappeared; on further follow-up, this increased to 89.6%. No patient had hypertension, CRI, or malignancy. Four patients (5%) developed nonrecurrent UTIs, none leading to renal scarring or growth impairment. These data suggest that subspecialty follow-up may be discontinued once contralateral hypertrophy and ipsilateral involution occur, assuming that the patient has not experienced hypertension, CRI, or UTI. These criteria are often met by 1 year of age, which would preclude repeated visits, uncomfortable investigations, and unnecessary costs.

Renal dysplasia and MRI: a clinician's perspective

Renal dysplasia is a common abnormality in children. The role of MRI in evaluating children with renal dysplasia is evolving. More information is clearly necessary before MRI replaces conventional imaging modalities. In order to appropriately use MRI, the radiologist must have an understanding of the clinical questions that are important in the management of children with renal dysplasia. This review provides background information on renal dysplasia for the pediatric radiologist. The focus is on unilateral disease, especially multicystic dysplastic kidneys, and bilateral dysplasia, which is the most common cause of kidney failure in children. The emphasis is on the important clinical issues, and the potential of MRI as a methodology for providing clinically useful information not otherwise available from other imaging modalities.

Diagnosis of aortic coarctation by tardus-parvus renal artery Doppler signal in an infant with multicystic dysplastic kidney: a case report

We report an infant with known unilateral multicystic dysplastic kidney (MCDK) who underwent renal ultrasonography and Doppler spectral waveform analysis for investigation of hypertension. A tardus-parvus waveform was demonstrated in the renal artery on the normal side suggesting either renal artery or more proximal stenosis. Coarctation of the aorta was subsequently demonstrated.

Ultrasound progression of prenatally detected multicystic dysplastic kidney

OBJECTIVES

To evaluate the sonographic involution of prenatally detected multicystic dysplastic kidney (MCDK).

METHODS

A total of 53 children with unilateral MCDK detected by prenatal ultrasonography between 1989 and 2004 were included in this analysis. All children received conservative management with follow-up visits every 6 months. Follow-up ultrasound examinations were performed at 6-month intervals during the first 2 years after birth and yearly thereafter. A linear mixed effect model was constructed, including MCDK length as the dependent variable and body size parameters and contralateral renal dimensions as independent variables.

RESULTS

The mean follow-up time was 68 months. A total of 334 ultrasound scans were analyzed. The ultrasound scan demonstrated partial or total involution of the MCDK in 48 cases (91%). A consistent negative correlation was found among MCDK length, patient age, and body size parameters. As a whole, the MCDK length reduction was estimated to be 0.29 mm/mo. The rate of reduction was not constant over time and was intense during the first 30 months of age. According to the regression model, MCKD reduced in length by 0.80 mm/mo during the first 30 months of age, 0.26 mm between 30 and 84 months old, and 0.30 mm in children older than 84 months.

CONCLUSIONS

Our results suggest a clear tendency of MCDK to decrease in size, with the rate of the involution greater during the first 30 months than the rate in older children.

Natural history of patients with multicystic dysplastic kidney-what followup is needed?

PURPOSE

Most clinicians recommend followup with annual ultrasound for patients with multicystic dysplastic kidney. The aim of this study was to determine whether followup ultrasound provides any clinical benefit.

MATERIALS AND METHODS

We retrospectively reviewed the charts of 73 patients who were diagnosed with multicystic dysplastic kidney between October 1991 and August 2005. Data were analyzed with respect to patient characteristics and followup information.

RESULTS

We identified 61 patients (43 boys and 18 girls) with adequate followup. A total of 49 patients (80%) were diagnosed prenatally and 12 (20%) postnatally. Associated urological anomalies were noted in 16 patients (26%). Median followup was 2.6 years (range 6 months to 37.5 years). Ultrasound examinations showed complete involution in 25 patients (41%) and partial regression in 18 (30%). The size of the multicystic dysplastic kidney increased in 1 patient (1.6%) and was unchanged in 17 (28%) without any pathological manifestations. Median age at complete involution was 2.1 years (range 36 days to 13.7 years). Patients with contralateral compensatory hypertrophy had more rapid complete involution. Urinary tract infection developed in 6 patients, of whom 1 was ultimately found to have reflux and 1 had ureteropelvic junction obstruction.

CONCLUSIONS

In our patients with unilateral multicystic dysplastic kidney ultrasound provided little clinically important information. Our data and a review of the literature suggest that once the diagnosis is made, no urological followup is needed. The primary care provider should monitor patients with multicystic dysplastic kidney for hypertension, abdominal mass and urinary tract infection.

Unilateral multicystic dysplastic kidney: long term outcomes

AIMS

To report the long term follow up of children with antenatally detected unilateral multicystic dysplastic kidney (MCDK) with documentation of complications, involution rate with time, and renal function at 10 years.

METHODS

Data were retrieved from a prospective regional registry of patients with MCDK between 1985 and 2004. Children were followed using a common protocol of investigation with follow up ultrasound scans (USS) at 2 (165 patients), 5 (117 patients), and 10 years (43 patients).

RESULTS

Serial USS showed that 33% of the MCDK kidneys had completely involuted at 2 years of age, 47% at 5 years, and 59% at 10 years. No patients developed hypertension, significant proteinuria, or malignancy, but two developed pelviureteric junction obstruction in the contralateral kidney. Twenty seven of 143 children (19%) had vesicoureteric reflux (VUR) (96% mild to moderate VUR) into the contralateral kidney with no difference in the incidence of urinary tract infections or renal scarring between those with or without VUR. The mean estimated glomerular filtration rate (GFR) was 86.4 ml/min/1.73 m2 (range 48-125) in 31 of 43 patients followed to 10 years.

CONCLUSIONS

Conservative management of unilateral MCDK is justified with clinical review and infrequent USS but longer term follow up continues in the 41% still with renal remnants at 10 years and those with impaired GFR. It is suggested that the initial micturating cystogram is deferred unless abnormal USS features are present in the contralateral kidney or ureter.

Perinatal assessment of hereditary cystic renal diseases: the contribution of sonography

The aims of this review article were to clarify the steps that may lead to a proper diagnosis of fetal and neonatal renal cystic diseases. All the hereditary cystic diseases are reviewed and a classification is proposed. The various sonographic patterns that can be used to ascertain the diagnosis are also reviewed. Finally, tables with differential diagnoses are presented to help the reader in the work-up of such pathologies.

Obstructive uropathy

Routine second trimester ultrasound screening has resulted in more infants diagnosed with antenatal hydronephrosis. Current recommendations suggest postnatal evaluation of all infants with a renal pelvic diameter >5 mm with ultrasound and voiding cystourethrogram (VCUG.) There are many etiologies of obstructive uropathy including ureteropelvic junction (UPJ) obstruction, ureterovesical junction (UVJ) obstruction, posterior urethral valves (PUV), prune belly syndrome, and vesicoureteral reflux (VUR). Obstructive uropathy can result in tubular damage and decreased nephron number. Tubular damage can result in sodium wasting, hyperkalemic acidosis, and nephrogenic diabetes insipidus. Most patients do not require renal replacement therapy in the neonatal period; however, chronic renal insufficiency can occur if the neonate has a significant reduction in nephron number or progressive renal damage from obstruction or infection.

Risk of hypertension with multicystic kidney disease: a systematic review

BACKGROUND

Children with multicystic kidney disease (MCKD) are increasingly managed conservatively, and are followed up throughout childhood because of the risk of hypertension highlighted in some reports. With this risk still poorly defined, the strategy and the duration of follow up do not seem to be based on evidence.

METHODS

Systematic review of the literature for all published cohort studies (prospective and retrospective) of children diagnosed to have unilateral MCKD and managed conservatively. Exclusion criteria were bilateral MCKD, and nephrectomy (not for hypertension) during the follow up period. For children with MCKD, the probability of developing hypertension during the follow up period was estimated.

RESULTS

From 29 reviewed studies, six cases of hypertension developed in 1115 eligible children. The mean probability of a child with unilateral MCKD developing hypertension was therefore 5.4 per 1000 (95% CI estimated at 1.9 to 11.7 per 1000).

CONCLUSION

Although the risk of hypertension in MCKD is low, the results of this study do not allow firm recommendations on the frequency and duration of blood pressure measurement follow up for these children. Large prospective cohort studies with a very long duration of follow up are needed.

Predictive factors of ultrasonographic involution of prenatally detected multicystic dysplastic kidney

OBJECTIVE

To evaluate possible predictive factors of involution on ultrasonography (US) or disappearance of a prenatally detected multicystic dysplastic kidney (MCDK).

PATIENTS AND METHODS

Forty-five children with unilateral MCDK detected by prenatal ultrasonography between 1989 and 2002 were analysed. All patients except one had (99m)Tc isotopic scintigraphy to confirm the absence of renal function in the MCDK. All children were managed conservatively with follow-up visits every 6 months, with US 6-monthly during the first 2 years of life and yearly thereafter. Survival was analysed using the Kaplan-Meier method to evaluate the involution of the MCDK, with differences between subgroups assessed using the two-sided log-rank test. Cox's regression model was applied for the multivariate analysis.

RESULTS

The mean (range) follow-up was 50 (12-167) months; in all, 279 ultrasonograms were taken, the mean (range) number per patient being 6 (3-10). US showed partial involution of the MCDK in 30 (67%) cases and complete involution in nine (20%). The absolute MCDK length remained almost unchanged in six children (13%). Univariate analysis showed that four variables were possibly associated with complete involution of the MCDK (gender, impalpable kidney, renal length at admission using two thresholds, 62 and 78 mm). After adjusting by Cox's model only a renal length at diagnosis of <62 mm remained associated with complete involution (relative risk 8, 95% confidence interval 0.98-68; P = 0.05).

CONCLUSION

These results suggest that only a renal length of <62 mm on initial US was predictive of complete involution of the MCDK during the follow-up.